Biometrics, broadly defined, is the measurement and analysis of unique physical or behavioral characteristics used to distinguish one individual from another and, thus, to identify or authenticate the identity of individuals. Identification is the process of identifying or detecting the identity of an unknown individual. Authentication is the process of verifying an individual as whom he or she claims to be. Common examples of biometrics used for identification and authentication include fingerprints, irises, retinas, and facial images.
The process of identification typically involves comparing a target biometric sample from an unknown individual against a large database of stored biometric information, in search of a match. However, a fingerprint database, for example, can include thousands upon thousands of instances of fingerprint data from a variety of sources. Although computer systems can automate the search, the matching process can run slowly because of several factors, including the sheer number of entries in the database, the nature and quality of the biometric information in the database and of the biometric sample, and the requisite degree of accuracy.